Fair Value Measurements - Level 3 Valuations (Details) - Level 3	Jun. 30, 2021
ImThera Medical, Inc. (“ImThera”) | Discounted cash flow | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.052
ImThera Medical, Inc. (“ImThera”) | Discounted cash flow | Probability of payment
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.85
ImThera Medical, Inc. (“ImThera”) | Monte Carlo simulation | Probability of payment
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.85
ImThera Medical, Inc. (“ImThera”) | Monte Carlo simulation | Revenue volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.325
ImThera Medical, Inc. (“ImThera”) | Minimum | Monte Carlo simulation | Risk-adjusted discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.120
ImThera Medical, Inc. (“ImThera”) | Minimum | Monte Carlo simulation | Credit risk discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.055
ImThera Medical, Inc. (“ImThera”) | Maximum | Monte Carlo simulation | Risk-adjusted discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.126
ImThera Medical, Inc. (“ImThera”) | Maximum | Monte Carlo simulation | Credit risk discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.064
CardiacAssist, Inc., doing business as TandemLife (“TandemLife”) | Discounted cash flow | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.033
CardiacAssist, Inc., doing business as TandemLife (“TandemLife”) | Discounted cash flow | Probability of payment
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.90